Semiconductor structure with a 2D-charge carrier layer and fabrication method

摘要

A unipolar electronic device is proposed which has a quasi-one-dimensional carrier channel having all the properties of an FET. This device can be produced very simply, has self-alignment and has linear instead of planar gates with very low capacitance. This makes a very high device operating frequency possible. The structure comprises an initially homogeneous 2D layer with high carrier mobility produced by epitaxy of, for example, GaAs. The conductivity of the n-type layer is locally destroyed by implanting focussed ions (for example, Ga<+> at 100 keV). The irradiated regions are still nonconductive even after illuminating the crystal with band-gap radiation at low temperature or room temperature. The insulation layer is inscribed along two paths on the chip, thus subdividing the 2D carrier layer into three regions which are insulated from one another. Source and drain are only linked by a narrow channel (44) whose width is continuously adjustable by means of a gate voltage simultaneously applied to the two gate regions relative to the source so as to result in a marked change in the carrier concentration and, consequently, in the channel resistance.